Method and system delivering a tracer to a flow

ABSTRACT

A tracer plug including a body configured to reside in a complementary opening in a separate structure. The body includes a tracer; a through-flow passage in the body; and wherein the tracer is disposed in fluid communication with the opening. A method for identifying fluid.

BACKGROUND

Many industries and particularly industries using boreholes to penetratea subsurface environment in a planetary body such as the Earth arebenefited by information about the movement of fluids. In an example,the industries may be interested in fluid flowing from formationsthrough which the boreholes extend into the borehole and what fluids areflowing from what distinct regions of the formations. One means forgaining this information is through the use of tracers placedstrategically in a borehole system such that fluids flowing past thetracers will pick up some of the tracer and carry it to the surfacewhere the produced fluids are analyzed. Different tracers are used indifferent areas so fluid with a particular tracer can be identified by aparticular region from which that fluid came. In a hydrocarbon well forexample, if water is produced and has a particular tracer, the operatorknows which zone is producing water and can take measures to reduce theinflux of water at that location, thereby increasing the amount oftarget fluid that is actually produced per volume of total fluidproduced.

The industry has created many types of tracers and many different typesof tracer delivery methods and systems but unfortunately, these systemsand methods are not precise enough. And with the advent of intelligentdownhole equipment, the ability to closely tailor the downholeenvironment begs for better tracer systems to take advantage of thegreater control that is available for the borehole. Unfortunatelyheretofore, a solution has not presented itself. The art would thereforewell receive new methods and systems that deliver tracers morespecifically.

SUMMARY

A tracer plug including a body configured to reside in a complementaryopening in a separate structure, the body comprising a tracer; athrough-flow passage in the body; and wherein the tracer is disposed influid communication with the opening.

A method for identifying fluid includes inserting a tracer plug asclaimed in claim 1 in a tubular string; running the string into aborehole; flowing fluid in the string; analyzing the flowed fluid; andidentifying a tracer in the fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 is a perspective view of a tubular system with perforations andillustrating several tracer plugs;

FIG. 2 is a cross section view of FIG. 1 taken along section line 2-2;

FIG. 3 is a cross section view of one embodiment of the tracer plug;

FIG. 4 is a cross section view of another embodiment of the tracer plug;

FIG. 5 is a cross section view of another embodiment of the tracer plug;

FIG. 6 is a cross section view of another embodiment of the tracer plug;

FIG. 7 is a cross section view of another embodiment of the tracer plug;

FIG. 8 is a cross section view of another embodiment of the tracer plug;and

FIG. 9 is a perspective partial cross section view of an embodiment of asystem including tracer plugs.

DETAILED DESCRIPTION

Referring to FIG. 1, a tubular system 10 having a structure 11 such as atubular string and having a tracer subsystem 12 is illustrated. It is tobe understood that the tubular system 10 in an embodiment is a string ina borehole for the purpose of hydrocarbon exploration, completion and/orproduction. Visible is one or more perforations 14 in the tubular 10.Perforations may be cylindrical, frustoconical (with the tip toward theradially inside of the tubular (shown in FIG. 2) or vice versa with thetip portion toward the outside of the tubular. It is further to beunderstood that the perforations 14 may be configured with threads(helical or wicker), interference fit smooth surfaces, in the case offrustocones, the angle may be a locking angle of less than about 7degrees, or other configuration intended to relatively secure thesubsystem 12 in the perforations 14. It is further noted that whilecircular patterns are shown and discussed above, there is no inherentimpediment to making the pattern another geometric shape, for examplesquare, other than making helical threads unusable for securement. Anyof the other securement concepts that allow for press in engagement willwork with a noncircular pattern of geometric shape.

It is to be understood that there is no reason for every perforation 14to be fitted with a tracer subsystem 12 and so there is shown in FIG. 1some perforations 14 without tracer subsystem 12 and some perforationswith subsystem 12. This is because the tracer in the tracer subsystemneed merely be added to an inflow from a particular region of aformation or other source and this can be accomplished with merely onetracer subsystem 12 in a particular section of tubular 10. The moretracer subsystems 12 employed in a particular region, the more tracerwill be released into the flow. If the tracer is the same in each tracersubsystem 12 then that will simply make detection easier but if thetracer subsystems 12 are each different, the granularity of detection oftypes of fluid coming from regions of the formation or other source willbecome smaller and smaller. To the extent other well systems exist tomanage fluid flow on a very granular level, having more tracersubsystems with distinct tracers is of great value.

Referring to FIGS. 3-8 various embodiments of the tracer subsystem 12are illustrated. The tracer subsystem 12 comprises a body 18 and in someembodiments a flange 20. He flange may help to prevent fluid flow aroundthe body and or simply assist in the installation procedure such as bybroadening the surface area available to an installer to hit with ahammer or press with another type of tool or present a larger dimensionrotational profile such as a hex head. In each case, the body 18comprises a through passage 22 (of any geometric shape) for fluidpassage from a source to a downstream destination. Fluid flowing throughthe passage 22 is exposed to a tracer 24 sufficiently to entrain tracermaterial with the fluid flow thereby allowing the location of fluidorigin to be identified if the fluid flows from a formation or if thefluid is an injection fluid, the path of the injected fluid can betraced by monitoring the tracer material progress in the formation.

In the embodiment of FIG. 3, the body is made up entirely of the tracer24 or is a composition including the tracer. In one iteration the bodycomprises a tracer carrying polypropylene resin such as the copolymerStat-Tech™ PP 000/000 AS commercially available from PolyOne, Inc. Insuch embodiments, including FIGS. 6 and 7, the material of the tracercarrier has sufficient inherent strength to withstand insertion into thetubular system 10 and to remain in a useful condition for a reasonableperiod of time during use. Other suitable tracer carrier materialsinclude: polyethylene resins, urea formaldehyde and melamineformaldehyde. Suitable chemical tracers for formaldehyde based carriersinclude amino naphthalene sulfonic acids and fluorescein. Suitableradioactive tracers may include radium or mesothorium; or artificialsuch as cobalt-60 or iridium-192.

Alternate tracer subsystem embodiments are also contemplated includingthose illustrated in FIGS. 4, 5 and 8 where a housing 26 is employed toprovide a structural framework for the tracer 24. In these embodiments,suitable tracer carrier materials include those noted above but furtherinclude relatively pliant polyurethane, polyurea, or a copolymer of thetwo that lack their own structural integrity to function independentlyof a housing 26. It is noted that the housing 26 and tracer 24 may havethe same shape (FIGS. 4 and 8) or may differ in shape (FIG. 5) as isdesired and appropriate for a particular usage. The shape of FIG. 5 maybe selected to support the tracer body against pressure on eithersurface 30 or surface 28.

In each embodiment of tracer subsystem, the passage 22 is present forfluid movement through the tracer subsystem 12 in a way that is inphysical contact with the tracer carrying material 24. While one passageis illustrated in each subsystem 12, it is to be appreciated that one ormore passages is intended and that duplicating the passages shown is anembodiment. Further, in one embodiment the plural passages will beparallel and in other embodiments, they may be divergent. Further still,in one embodiment the passages are created by tracer carrier materialporosity. In each case though they will extend between one axial surface28 of the subsystem 12 and another axial surface 30 of the subsystem.Also, in some embodiments, there may be a desire to maintain a higherpressure drop across the tracer subsystem than that provided byproximate perforations 14 to preferentially flow only local fluidthrough the passage 22. This will reduce contamination of the tracedfluid from other zones flowing axially and then through the passage 22.It is to be appreciated that the subsystems when being inserted inanother structure such as the tubular string 11, surface 28 may bepositioned toward an outside of the structure and surface 30 toward theinside of the structure or vice versa. Further, the surfaces may bepositioned in either direction of intended flow fluid i.e. from surface28 through passage 22 toward surface 30 or vice versa.

Referring to FIGS. 4 and 5, the housing 26 is illustrated with threads32 (helical threads, wicker threads, body lock ding type threads, etc.)to provide attachment to the structure 11 either with a complementaryengagement configuration or by interference and rotationally or by pressfit. It is to be understood that the attachment features such as shownon the housing 26 in FIGS. 4 and 5 may be presented on any of the otherconfigurations of FIGS. 3-8 whether or not a housing is extant. This isintended to include providing such features directly on the tracer 24 inembodiments not having a housing or where tracer is otherwise exposed ina location where the feature would be present.

Referring to FIG. 9, an embodiment of a tubular system 10 for a boreholethat is designed to produce a fluid resource such as a hydrocarbon fluidis illustrated. The tubular system 10 will as is understood by one ofordinary skill in the related arts made a part of a tubular string 11that extends to surface and likely further downhole as well. The systemcomprises a tubular structure 11 having one or more ports 14 and havingone or more tracer subsystems 12 disposed in the tubular structure 11.Radially outwardly of the tubular structure 11 is an inner shroud 40. Itis noted here that in embodiments hereof, a single shroud or screen orscreen and shroud, for example, may be employed radially outwardly ofthe structure 11. The embodiment illustrated in FIG. 9 comprises anumber of radially outward structures that may be all employed or mixedand matched if desired. It is also to be understood that someembodiments may require one of more of these structures to be disposedradially inwardly of the structure 11 for certain utilities. Each ofthese constructions is contemplated and disclosed herein. Returning toFIG. 9, radially outwardly of the inner shroud 40 is a mesh 42, whichmay be of any type normally employed in the downhole industry to excludeparticulate matter. Radially outwardly of the mesh 42 is illustrated anouter shroud 44 followed by a shape memory polymer 46 such as GeoFORM™filter material available from Baker Hughes Incorporated, Houston, Tex.Again, it is to be understood that the order of components shown is butone embodiment and that different orders of the same components as wellas omission of some or duplication of some components is alsocontemplated. In the particular embodiment illustrated a seal ring 48whose purpose it is to envelope the shape memory polymer 46 to provide aparticulate seal and an end ring 50 are assembled to the system 10. Endring 50 may be secured in some instances by fasteners 52, which may beof the serrated variety in some iterations.

The system 10 as disclosed herein simplifies construction and placementof tracer materials as well as enabling flush mounting of the tracersubsystem 12 and little or no modification of existing downhole tools toprovide for tracer function while also making tracer subsystemsavailable for tools having minimal void space for tracer subsystems ofthe prior art. Further, because of the particular embodiments disclosed,axial flow leaching is reduced, thereby making fluid locationidentification more accurate than available in prior art tracer systems.Further, because of the configuration of the tracer subsystem 12disclosed herein, installation in any specific flow path is facilitatedand contemplated.

Set forth below are some embodiments of the foregoing disclosure:

Embodiment 1

A tracer plug comprising: a body configured to reside in a complementaryopening in a separate structure, the body comprising a tracer; athrough-flow passage in the body; and wherein the tracer is disposed influid communication with the opening.

Embodiment 2

The tracer plug of embodiment 1 wherein the body is tubular.

Embodiment 3

The tracer plug of embodiment 1 wherein the body is cylindrical.

Embodiment 4

The tracer plug of embodiment 1 wherein the body is threaded.

Embodiment 5

The tracer plug of embodiment 1 wherein the body includes wickers.

Embodiment 6

The tracer plug of embodiment 1 wherein the body is cylindrical.

Embodiment 7

The tracer plug of embodiment 1 wherein the body is frustoconical.

Embodiment 8

The tracer plug of embodiment 1 wherein the body houses the tracer.

Embodiment 9

The tracer plug of embodiment 1 wherein the body consists of the tracer.

Embodiment 10

The tracer plug of embodiment 1 wherein the passage is one or morepassages.

Embodiment 11

The tracer plug of embodiment 1 wherein the plug further includes ahousing disposed about the body.

Embodiment 12

The tracer plug of embodiment 11 wherein the housing is threaded.

Embodiment 13

The tracer plug of embodiment 11 wherein the housing is wickered.

Embodiment 14

A borehole system comprising: a tubular having a port therein; a tracerplug as claimed in claim 1 in the port. The borehole system as claimedin claim 14 further comprising a screen radially outward of the tubularand tracer plug.

Embodiment 15

The borehole system of embodiment 15 wherein the screen is a metalscreen.

Embodiment 16

The borehole system of embodiment 15 wherein the screen is a shapememory material.

Embodiment 17

A method for identifying fluid comprising: inserting a tracer plug asclaimed in claim 1 in a tubular string; running the string into aborehole; flowing fluid in the string; analyzing the flowed fluid; andidentifying a tracer in the fluid.

Embodiment 18

The method of embodiment 18 wherein the inserting is of different tracerplugs in different regions of the tubular string and recording locationsfor each different tracer.

Embodiment 19

The method of embodiment 18 further including determining from where theflowed fluid emanated.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Further, it should further be noted that the terms “first,”“second,” and the like herein do not denote any order, quantity, orimportance, but rather are used to distinguish one element from another.The modifier “about” used in connection with a quantity is inclusive ofthe stated value and has the meaning dictated by the context (e.g., itincludes the degree of error associated with measurement of theparticular quantity).

The teachings of the present disclosure may be used in a variety of welloperations. These operations may involve using one or more treatmentagents to treat a formation, the fluids resident in a formation, awellbore, and/or equipment in the wellbore, such as production tubing.The treatment agents may be in the form of liquids, gases, solids,semi-solids, and mixtures thereof. Illustrative treatment agentsinclude, but are not limited to, fracturing fluids, acids, steam, water,brine, anti-corrosion agents, cement, permeability modifiers, drillingmuds, emulsifiers, demulsifiers, tracers, flow improvers etc.Illustrative well operations include, but are not limited to, hydraulicfracturing, stimulation, tracer injection, cleaning, acidizing, steaminjection, water flooding, cementing, etc.

While the invention has been described with reference to an exemplaryembodiment or embodiments, it will be understood by those skilled in theart that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the invention.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims. Also, in the drawings and the description, there have beendisclosed exemplary embodiments of the invention and, although specificterms may have been employed, they are unless otherwise stated used in ageneric and descriptive sense only and not for purposes of limitation,the scope of the invention therefore not being so limited.

1. A tracer plug comprising: a body configured to reside in acomplementary opening in a separate structure, the body comprising atracer; a through-flow passage in the body; and wherein the tracer isdisposed in fluid communication with the opening.
 2. The tracer plug asclaimed in claim 1 wherein the body is tubular.
 3. The tracer plug asclaimed in claim 1 wherein the body is cylindrical.
 4. The tracer plugas claimed in claim 1 wherein the body is threaded.
 5. The tracer plugas claimed in claim 1 wherein the body includes wickers.
 6. The tracerplug as claimed in claim 1 wherein the body is cylindrical.
 7. Thetracer plug as claimed in claim 1 wherein the body is frustoconical. 8.The tracer plug as claimed in claim 1 wherein the body houses thetracer.
 9. The tracer plug as claimed in claim 1 wherein the bodyconsists of the tracer.
 10. The tracer plug as claimed in claim 1wherein the passage is one or more passages.
 11. The tracer plug asclaimed in claim 1 wherein the plug further includes a housing disposedabout the body.
 12. The tracer plug as claimed in claim 11 wherein thehousing is threaded.
 13. The tracer plug as claimed in claim 11 whereinthe housing is wickered.
 14. A borehole system comprising: a tubularhaving a port therein; a tracer plug as claimed in claim 1 in the port.15. The borehole system as claimed in claim 14 further comprising ascreen radially outward of the tubular and tracer plug.
 16. The boreholesystem as claimed in claim 15 wherein the screen is a metal screen. 17.The borehole system as claimed in claim 15 wherein the screen is a shapememory material.
 18. A method for identifying fluid comprising:inserting a tracer plug as claimed in claim 1 in a tubular string;running the string into a borehole; flowing fluid in the string;analyzing the flowed fluid; and identifying a tracer in the fluid. 19.The method as claimed in claim 18 wherein the inserting is of differenttracer plugs in different regions of the tubular string and recordinglocations for each different tracer.
 20. The method as claimed in claim18 further including determining from where the flowed fluid emanated.